Cool! A cloud in a bottle! You can make one yourself by watching this little how-to. You'll need a bottle, a bike pump and a little attachment from the hardware store.

Have you ever wondered how clouds form? Clouds are formed when water vapor is cooled enough to form tiny water droplets. This is exactly what happens when moist air rises in the atmosphere, cools, and water droplets form into clouds. Making your own cloud is a popular experiment in many science books, but you should know that the results are not very striking. Yes, you'll see a very faint cloud (very faint), but it's a little tricky.